labetalol

a beta-adrenergic blocking agent with some alpha-adrenergic blocking agent activity, administered orally or intravenously as the hydrochloride salt as an antihypertensive agent.

labetalol

(la-bet-a-lole) ,

Trandate

(trade name) Pregnancy Category: C

Indications

Action

Pharmacokinetics

Time/action profile (cardiovascular effects)

ROUTE	ONSET	PEAK	DURATION
PO	20 min–2 hr	1–4 hr	8–12 hr
IV	2–5 min	5 min	16–18 hr

Contraindications/Precautions

Adverse Reactions/Side Effects

Central nervous system

• fatigue (most frequent)
• weakness (most frequent)
• anxiety
• depression
• dizziness
• drowsiness
• insomnia
• memory loss
• mental status changes
• nightmares

Ear, Eye, Nose, Throat

• blurred vision
• dry eyes
• intraoperative floppy iris syndrome
• nasal stuffiness

Respiratory

• bronchospasm
• wheezing

Cardiovascular

• arrhythmias (life-threatening)
• bradycardia (life-threatening)
• chf (life-threatening)
• pulmonary edema (life-threatening)
• orthostatic hypotension (most frequent)

Gastrointestinal

• constipation
• diarrhea
• nausea

Genitourinary

• erectile dysfunction (most frequent)
• ↓ libido

Dermatologic

• itching
• rashes

Endocrinologic

• hyperglycemia
• hypoglycemia

Musculoskeletal

• arthralgia
• back pain
• muscle cramps

Neurologic

• paresthesia

Interactions

Drug-Drug interaction

General anesthesia and verapamil may cause additive myocardial depression.Additive bradycardia may occur with digoxin, verapamil, or diltiazem.Additive hypotension may occur with other antihypertensives, acute ingestion of alcohol, or nitrates.Concurrent thyroid administration may ↓ effectiveness.May alter the effectiveness of insulin or oral hypoglycemic agents (dose adjustments may be necessary).May ↓ the effectiveness of adrenergicbronchodilators and theophylline.May ↓ beneficial beta cardiovascular effects of dopamine or dobutamine.Use cautiously within 14 days of MAO inhibitor therapy (may result in hypertension).Effects may be ↑ by propranolol or cimetidine.Concurrent NSAIDs may ↓ antihypertensive action.

Route/Dosage

Availability (generic available)

Nursing implications

Nursing assessment

• Monitor BP and pulse frequently during dose adjustment and periodically during therapy. Assess for orthostatic hypotension when assisting patient up from supine position.
• Check frequency of refills to determine compliance.
• Patients receiving labetalol IV must be supine during and for 3 hr after administration. Vital signs should be monitored every 5–15 min during and for several hours after administration.
• Monitor intake and output ratios and daily weight. Assess patient routinely for evidence of fluid overload (peripheral edema, dyspnea, rales/crackles, fatigue, weight gain, jugular venous distention).
• Lab Test Considerations: May cause ↑ BUN, serum lipoprotein, potassium, triglyceride, and uric acid levels.
  • May cause ↑ ANA titers.
  • May cause ↑ in blood glucose levels.
  • May cause ↑ serum alkaline phosphatase, LDH, AST, and ALT levels. Discontinue if jaundice or laboratory signs of hepatic function impairment occur.
Monitor patients receiving beta blockers for signs of overdose (bradycardia, severe dizziness or fainting, severe drowsiness, dyspnea, bluish fingernails or palms, seizures). Notify health care professional immediately if these signs occur.
• Glucagon has been used to treat bradycardia and hypotension.

Potential Nursing Diagnoses

Decreased cardiac output (Side Effects)
Noncompliance (Patient/Family Teaching)

Implementation

• high alert: IV vasoactive medications are inherently dangerous. Before administering intravenously, have second practitioner independently check original order, dosage calculations, and infusion pump settings.
• Do not confuse labetalol with Lamictal.
• Discontinuation of concurrent clonidine should take place gradually, with beta blocker discontinued first. Then, after several days, discontinue clonidine.
• Oral: Take apical pulse prior to administering. If <50 bpm or if arrhythmia occurs, withhold medication and notify health care professional.
  • Administer with meals or directly after eating to enhance absorption.

• Intravenous Administration

• Diluent: Administer undiluted.Concentration: 5 mg/mL.
• Rate: Administer slowly over 2 min.
• Continuous Infusion: Diluent: Add 200 mg of labetalol to 160 mL of diluent. May also be administered as undiluted drug. Compatible diluents include D5W, 0.9% NaCl, D5/0.9% NaCl, and LR.Concentration: Diluted: 1 mg/mL; Undiluted: 5 mg/mL.
• Rate: Administer at a rate of 2 mg/min. Titrate for desired response. Infuse via infusion pump to ensure accurate dose.
• Y-Site Compatibility: alemtuzumab, alfentanil, amikacin, aminocaproic acid, aminophylline, amiodarone, anidulafungin, argatroban, ascorbic acid, atracurium, atropine, aztreonam, bivalirudin, bleomycin, bumetanide, buprenorphine, butorphanol, calcium chloride, calcium gluconate, carboplatin, carmustine, caspofungin, cefazolin, ceftazidine, chlorpromazine, cisplatin, clonidine, cyanocobalamin, cyclophosphamide, cyclosporine, dactinomycin, daptomycin, dexmedetomidine, digoxin, diltiazem, diphenhydramine, dobutamine, docetaxel, dopamine, doripenem, doxorubicin hydrochloride, doxycycline, enalaprilat, ephedrine, epinephrine, epirubicin, epoetin alfa, eptifibatide, ertapenem, erythromycin lactobionate, esmolol, etoposide, etoposide phosphate, famotidine, fenoldopam, fentanyl, fluconazole, fludarabine, fluorouracil, folic acid, ganciclovir, gemcitabine, gentamicin, glycopyrrolate, granisetron, hydromorphone, idarubicin, ifosfamide, imipenem/cilastatin, irinotecan, isoproterenol, levofloxacin, lidocaine, linezolid, lorazepam, magnesium sulfate, mannitol, mechlorethamine, meperidine, methoxamine, methyldopate, methylprednisolone sodium succinate, metoclopramide, metoprolol, metronidazole, midazolam, milrinone, mitoxantrone, morphine, multivitamins, mycophenolate, nalbuphine, naloxone, nicardipine, nitroglycerin, nitroprusside, norepinephrine, octreotide, ondansetron, oxacillin, oxaliplatin, oxytocin, palonosetron, pamidronate, pancuronium, papaverine, pemetrexed, pentamidine, pentazocine, pentobarbital, phenobarbital, phentolamine, phenylephrine, phytonadione, potassium acetate, potassium chloride, potassium phosphates, procainamide, prochlorperazine, promethazine, propofol, propranolol, protamine, pyridoxime, quinupristin/dalfopristin, ranitidine, rocuronium, sodium acetate, sodium bicarbonate, streptokinase, succinylcholine, sufantanil, tacrolimus, telavancin, teniposide, theophylline, thiamine, thiotepa, ticarcillin/clavulanate, tigecycline, tirofiban, tobramycin, tolazoline, trimetaphan, vancomycin, vasopressin, vecuronium, verapamil, vincristine, vinorelbine, voriconazole, zoledronic acid
• Y-Site Incompatibility: acyclovir, amphotericin B cholesteryl, amphotericin B colloidal, amphotericin B lipid complex, amphotericin B liposome, azathioprine, cefotaxime, cefotetan, cefoxitin, ceftaroline, ceftriaxone, cefuroxime, dantrolene, dexamethasone sodium phosphate, diazepam, diazoxide, hydrocortisone sodium succinate, indomethacin, insulin, ketorolac, micafungin, nesiritide, paclitaxel, pantoprazole, penicillin G, phenytoin, piperacillin/tazobactam, thiopental, warfarin

Patient/Family Teaching

• Instruct patient to take medication as directed, at the same time each day, even if feeling well; do not skip or double up on missed doses. Take missed doses as soon as possible up to 8 hr before next dose. Abrupt withdrawal may precipitate life-threatening arrhythmias, hypertension, or myocardial ischemia.
• Advise patient to make sure enough medication is available for weekends, holidays, and vacations. A written prescription may be kept in wallet in case of emergency.
• Teach patient and family how to check pulse and BP. Instruct them to check pulse daily and BP biweekly. Advise patient to hold dose and contact health care professional if pulse is <50 bpm or BP changes significantly.
• May cause drowsiness or dizziness. Caution patients to avoid driving or other activities that require alertness until response to the drug is known. Caution patients receiving labetalol IV to call for assistance during ambulation or transfer.
• Advise patients to make position changes slowly to minimize orthostatic hypotension, especially during initiation of therapy or when dose is increased. Patients taking oral labetalol should be especially cautious when drinking alcohol, standing for long periods, or exercising, and during hot weather, because orthostatic hypotension is enhanced.
• Caution patient that this medication may increase sensitivity to cold.
• Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking any Rx, OTC, or herbal products, especially cold preparations, concurrently with this medication. Patients on antihypertensive therapy should also avoid excessive amounts of coffee, tea, and cola.
• Patients with diabetes should closely monitor blood glucose, especially if weakness, malaise, irritability, or fatigue occurs. Medication may mask tachycardia and increased BP as signs of hypoglycemia, but dizziness and sweating may still occur.
• Advise patient to notify health care professional if slow pulse, difficulty breathing, wheezing, cold hands and feet, dizziness, light-headedness, confusion, depression, rash, fever, sore throat, unusual bleeding, or bruising occurs.
• Instruct patient to inform health care professional of medication regimen prior to treatment or surgery.
• Advise patient to carry identification describing disease process and medication regimen at all times.
• Hypertension: Reinforce the need to continue additional therapies for hypertension (weight loss, sodium restriction, stress reduction, regular exercise, moderation of alcohol consumption, and smoking cessation). Medication controls but does not cure hypertension.

Evaluation/Desired Outcomes

• Decrease in BP.